PRODUCTION OF PRECIPITATION HARDENING TYPE MARTENSITIC STAINLESS STEEL EXCELLENT IN COLD FORGEABILITY

摘要

PROBLEM TO BE SOLVED: To produce a precipitation hardening type stainless steel excellent in cold forgeability by subjecting a steel contg. specified metals by specified weight ratios and also in such a manner that the weight ratio between specified metals satisfies specified value to hot rolling and thereafter executing heat treatment under specified conditions. ;SOLUTION: This is a method for producing a precipitation hardening type martensitic stainless steel excellent in cold forgeability in which a steel having a compsn. contg., by weight, ≤0.050% C, ≤0.60% Si, ≤0.80% Mn, ≤0.010% S, 2.5 to 4.0% Cu, 3.5 to 6.0% Ni, 14.00 to 16.00% Cr, 0.15 to 0.55% Nb and ≤0.030% N, also satisfying ≤0.070% C+N ≥5.00 Nb/(C+N), and the balance Fe with impurity elements is subjected to hot rolling, is thereafter cooled to a room temp., is subsequently heated at 980 to 1080°C, is held to the temp. for 15min to 6hr, is then cooled to 800 to 880°C at a rate of ≤500°C/hr, is held to this temp. for 1 to 16hr and is thereafter cooled to a room temp.;COPYRIGHT: (C)1997,JPO